Method and apparatus for flattening sheet glass



' Oct. 26", 1926.

1,604,823 J. HAR-rzELl.`

METHOD AND APPARATUS FOR FLATTENING SHEET GLAss IFiled Oct. i 17, 1924 2Sheets-Sheet 1 MA wig, ABA

, l lmm J. HARTZELL METHOD AND APPARATUS FQR FLATTENING SHEET GLSS Filedoct. 17, 1924 2 shane-sheath JIL.7

Patented @et 265, i925.

ien stares Peteur ortie,

JOHN HARTZELL, OF ARNOLD, PENNSYLVANIA, ASSIGNOR TO WNDOW GLASS MA-CHINE COMPANY, F PIT'ISBRG-I-I, PENNSYLVANA, A CORPORATION OF .NEW

J ERSEY.

METHOD AND AP'ARATUS FOR FLATTENING- SHEET GLASS.

Application led October 17, 1924. Serial No. 744,154.

This invention relates to the flattening of sheet glass, such as windowglass, and is herein shown as applied to the cylinder process of glassmanufacture, although certain features of the invention are equallyapplicable to the sheet drawing process of glass making. y

In the flattening of window glass, the glass to be flattened isgenerally supported upon a substantially continuous surface, which inthe cylinder process tales the form of a flattening stone and in thesheet drawing process is the socalled chain table; and heat is appliedabove the glass to raise the same above the annealing temperature. rTheglass is then smoothed to a plane sheet either by rubbing or stretching,and is then per mitted to cool while still supported by such surfaceuntil it reaches a temperature where it may be transferred to othersupport-ing devices for cooling.

ln the cylinder process, the flattening `stones are generally mountedupon a horizontal wheel adapted for moving the stones to successivepositions, and in the sheet drawing process the chain table iscont-inuous, so that in either process any particular supporting surfacewill first support the glass as it is heated and flattened, and then asit cools; and will then be out of contact with the glass until thecyclehas been completed and it is again available for supporting theunflattened glass. 1rWhen high speeds are attained or when heavy glassis being flattened, it is found that the supporting surface frequentlybecomes almost as hot as the flattening chamber proper, and this causesburning of the glass with a marked reduction in quality.

l provide for circulating cooling fluid below the supporting surfaceduring a part of its cycle of movement and thus maintaining it at adesired relatively low temperature. vWith my apparatus it is possible toattain high flattening speeds and still hold the flattening surfaces tosuch a low temperature that burning of the glass is practicallyeliminated.

The hot gases which are used for bringing the glass up to temperatureare generally taken ed inthe path followed by the glass after it hasbeen attened, and since the gases are continually losing heat, theyserve to permit a reduction in temperature of the glass but retard thiscooling sufliciently to prevent distortion or cracking of the glass.` Inorder to reduce the glass to the desired temperature at the proper timeand also to materially aid in reducing the temperature of a supportingsurface before it again comes in contact with the glass, l provide forwithdrawing at least a portion of these hot gases before the end of theglass travel on the supporting surface. Y

In the drawings, showing my preferred form of apparatus as applied tothe cylinder process of making window glass:

Figure 1 is a vertical section through a flattening oven embodying myinvention and taken on the line l--I of Figure 2;

Figure 2 is a horizontal section through the'flattening oven talren onthe line fL-H of Figure 1;

Figure 3 is a horizontal section taken on the line Hlwll of Figure 1;and

Figure 4l is a vertical section taken on the line IV-V of Figure 2.

ln the illustrated embodiment of the invention, there is shown aflattening oven having mounted therein a flattening wheel 2 carrying aplurality of flattening stones These flattening stones are adapted to hesuccessively in the several positions shown in F igurev 2 upon periodicrotation of the flattening wheel 2A The Oven comprises the flatteningoven proper, indicated bythe reference character 4;, the socalled dummyoven 5 and the 'cooling and piling oven 6. These various portions areseparated by depending mantles 7 which extend to within a short/distancefrom the top of the stones, as shown in Figure l. Glass is supplied tothis oven in the form of shawls throughla stick-hole 8 and is partiallyheated therein. The flattener, workingv through an opening 9, picks uplthe shawl and lays it on that flattening stone 3 which is at the time inthe flattening oven d.

4Heat is supplied to the oven by a suitable burner 10 in a burner'pit-11 and sweeps up over the stick-hole arch 12 to the attening oven 4.-"l`he heat is radiated from the oven arch 13. and quickly raises theglass to the ator then rubs the glass until it is flat and the wheel isrotated through an angle of o to bring the flattened sheet into thedummy oven 5.

The hot gases in the flattening oven escape therefrom partly through thestick-hole 8 and partly through the opening 9, but a material portion,of these hot gases pass under the mantles 7 to the dummy oven and thecooling and piling oven. A large portion of the gases passing under theniantlcs is falten offthrough the leer tunnel 14.

It will be seen from the above that a certain portion of the hot gasesfollow a substantially well defined path, as indicated by arrows inFigure 2, this path taking the gases out of the flattening oven 4 andunder the mantle to the dummy oven 5, then from the dummy oven under themantle to the cooling and piling oven 6 and then down the leer tunnel1lto atmosphere. e y e p While the first flattened sheet of glass islying in the dummy oven, a succeeding shawl is flattened in theflattening oven 4s and the wheel is rotated another 90, bringing a freshstone into the flattening oven and rotating the firstkfiattened sheet ofglass into the cooling and piling oven. Vhen the wheel is again rotated,the sheet is cool enough to be handled land is in position to be liftedon the leer rods 15, which is done by the flattener with a suitable forkthrough the opening 16. The next rotation of the wheel brings theflattening Vstone 3 which was originally in the flattening oven again inposition to receive the unflattened sheet of glass and the cyclecontinues during the period of operation.

It will be seen that if the hot gases play on the flattening stone overan extended periodof time, as frequently occurs iii operation, thestones will soon attain a temperature very close to that of the heatinggases. When this condition occurs, Vthe glass becomes too highly heatedon the under side and is burned by the flattening surface. In order toprevent this, I provide a division wall 17in the cellar of the ovenbelow the wheel 2. This division wall extends from the front thereofAtoward the back in such manner as to divide that portion of the ovenlying below the flattening oven proper and the dummy oven from thatportion lying below the cooling and piling oven.V vets seen in Figure 3,this wall comprises radial portions 17 and a central cylindrical portion17. The portie-i117a is providedV in order to give clearance for thewheel structure and for the turning mechanism, which 4comprises a bevelgear 18 and lcori-nected ydriving mechanism therefor,l Anot shown. The':division wall is therefore-effective for dividing the `cellar, intoAVportions 19.' and; 20, the portion 19 lying below the Iattening desiredflattening temperature. The operoven proper and the dummy oven, and theportion 2O lying below the cooling and piling oven. Obviously, sinceheat is applied to the stones principally in the flattening oven li, itis desirable to supply the cooling fluid as provided by my invention inthe portion 19. This is accomplished by providing a stack 21 having apassage 22 communicatingwith the space. 19. A damper 23 is preferablyprovided for regulating the amount of cooling fluid which is circulatedunder the wheel. The cooling air enters the space 19 through the variouscrevices of the oven and also through the openings usually provided,such as the clean-out door 26. The circulation thus set up beneath theflattening wheel effectually reduces the temperature of the flatteningstones and prevents burning of the glass.

In order to further cool the stones, I provide a passage 1:24 connectingthe stack 21 with the dummy oven 5. This connection is effective forshortcircuiting a material portion ofthe heating gases passing under themantles 7 and thus reducing the soaking heat to which the stones areusually exposed in the dummy oven and the cooling and piling oven.V Inorder toeffectively regulate the apparatus, a Ydainperd25 is preferablypnovided in the passage 21h n l l I thus `providean apparatus whereinthe flattening may be accomplished at high speeds and without theburning ofthe product` which has been heretofore experienced undercertain working conditions. VThe apparatus may be readily adjusted tosecure desired results, and it is found in operation to be exceedinglyeffective for the purposes set forth.

Y While Iliave illustrated a preferred embodiment of the invention asapplied to the cylinder process ofl glass manufacture, it will beunderstood that my invention is not limited to suoli an embodiment butmay be otherwise carried out within the scope of the l following claims:

I claim: s

Y 1. Glass flattening apparatus, including a flattening oven, aflattening wheel therein having flattening surfaces adapted to be movedto successive positions by rotation of the wheel, means for supplyingheat above one of such positions, means for passing cooling fluid belowsaid position and a succeeding position, apartition between suchpositions, and means for lwithdrawing hot gases yfrom above Asaidsucceeding position.I

2. Glass flattening apparatus, including a flattening even, awheeltherein havingr a plurality of attening surfaces adapted to bemolved tosuccessive positions, and a division `wall` below the..wlieelseparating the' space below 'certainl of, said positions from the spacelloelow @there a eine' steaming appara-,11s, siciliani;

lll() a flattening oven, a Wheel therein having a plurality offlattening surfaces adapted to be moved to successive positions, and adivision vvall belon7 the Wheel separating the space below certain ofsaid positions from the space below others, the Wall having a centerportion adapted to accommodate a turning means for the Wheel.

Il. ln the method of flattening glass, the steps consisting insupporting the glass to be flattened on successive supporting surfaces,applying heat above the glass, and passing cooling fluid under aplurality of such supporting surfaces successively.

5. In the method of flattening glass, the steps consisting in supportingthe glass to be flattened on a plurality of successive suporting means,and supplying cooling fluid llelovv the supporting means for only aportion of the time.

6. In the method of flattening glass, the steps consisting in supportingthe glass to be flattened ona plurality of successive supportingelements, moving the supporting surfaces in an endless path, and passingcooling fluid belouT the supporting means during a portion only of theirtravel in said path.

7. ln the method of flattening glass,l the steps consisting insupporting and flattening the glass on successive supporting elements,moving the supports in an orbital path and specially cooling thesupports during a portion only of their travel.

8. Apparatus for flattening glass comprising a flattening Wheel andmeans for supplying cooling fluid thereto, said means being effectivefor supplying cooling fluid to a portion only of the Wheel at one time.

9. Apparatus for flattening glass comprising a plurality of supportingelements adapted to move successively through a plurality of stationsand means for applying cooling air to a portion only of' the elements atany one time, said means being located adjacent a station and thesupporting elements moving successively into cooperative relation withthe cooling means.

lO, Apparatus for flattening glass comprising a. chamber, a flatteningWheel Within the chamber, a division Wall extending into proximity Withthe Wheel to form a smaller chamber adjacent which only a portion of theWheel may reside at any one time, and means for specially applyingcooling fluid to such smaller chamber.

1l. Apparatus for flattening glass comprising a chamber, a flatteningWheel Within the chamber, a division Wall'extending into proximity withthe Wheel to form a smaller chamber adjacent which only a portion of theWheel may reside at any one time, means for specially applying coolingfluid to such smaller chamber, and means for regulating the quantity ofcooling fluid supplied.

In testimony whereof I have hereunto set my hand.

JOHN HARTZELL.

